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Experts say smoking can speed up the aging process as well as increase the risk of cancer. Stephan Geyer/Getty Images
  • Researchers are reporting that smoking causes damage to chromosomes in blood cells that can cause premature aging.
  • They note that premature aging can reduce lifespan as well as quality of life.
  • Experts say quitting smoking could reduce the risk of chromosome damage.

Smoking causes chromosomal damage in white blood cells that can accelerate the aging process, according to a new study.

In analyzing the study, which involved nearly half a million, researchers reported that smokers were more likely to have shorter end fragments of chromosomes, called telomeres, which are known indicators of aging and cells’ ability to repair and regenerate themselves.

The findings were presented at the European Respiratory Society International Congress in Milan, Italy, this week. The research hasn’t been published yet in a peer-reviewed journal.

Shorter telomeres were related to both smoking status and the quantity of cigarettes smoked, said Siyu Dai, PhD, a study author and an assistant professor in the School of Clinical Medicine at Hangzhou Normal University in China.

“In other words, smoking can accelerate the process of aging, while quitting may considerably decrease the related risk,” Dr. Dai said.

Past research has linked telomere length in white blood cells to smoking, but experts note that the new study establishes a causal link.

“This study addresses the question whether smoking affects telomere lengths,” said Dr. Jonathan Grigg, chair of the European Respiratory Society Tobacco Control Committee, in a press statement.

“Telomeres protect the ends of chromosomes. If telomeres become short, cells can no longer divide successfully, and they die.”

“This study adds to the growing body of evidence that smoking accelerates biological age,” Dr. Danny Nguyen, a medical oncologist and hematologist practicing at the City of Hope Orange County Lennar Foundation Cancer Center in California who was not involved in the study.

“Tobacco smoke is toxic, and the cell damage it causes isn’t limited to visible symptoms like weathered skin,” he told Medical News Today.

Nguyen added that research shows “individuals with either very short or very long telomeres are both at higher risk of cancer,” although scientists don’t yet know why.

Dr. Dai and Feng Chen, PhD, a researcher at the Chinese University of Hong Kong, based their findings on an analysis of genetic and health data from the UK Biobank.

Information on leucocyte telomere length taken from patient blood tests was correlated to current, previous, and non-smoking status as well as the level of addiction to smoking and the quantity of cigarettes consumed.

A randomization technique based on inherited genetic variations was used to establish causality.

“This study applied Mendelian randomization, a well-known method for providing good levels of evidence and being able to show causal relationships, to support previous, observational studies suggesting that smoking causes aging, while quitting may reverse this effect,” noted Dr. Grigg.

“We found that current smoking status was statistically significantly associated with shorter leukocyte telomere length, whereas previous smokers and people who had never smoked didn’t show significantly shorter leukocyte telomere length,” said Dr. Dai.

“Among people who used to smoke, there was a trend toward shorter telomere length, but this was not statistically significant.”

People who smoked the greater number of cigarettes had significantly shorter leukocyte telomere length, added Dr. Dai.

“In recent years, observational studies have linked shortened leukocyte telomere length with many diseases, such as cardiovascular disease, diabetes, and muscle loss. This means that the effect of smoking on telomere length probably plays a critical role in these diseases, although more research is needed to understand the underlying mechanisms.”

— Siyu Dai, PhD, study author

Dr. William Dale, the director of the Center for Cancer and Aging at City of Hope who was not involved in the study, told Medical News Today that smoking is known to shorten lifespan by an average of about 10 years. He added that aging is an independent risk factor for cancer.

Researchers have not quite been able to “connect the dots” between smoking, cancer, and aging, Dr. Dale said, but the new research suggests telomere damage “might be one piece of that.”

Dr. Dale added that premature aging related to chromosomal damage means “you’re still going to shorten your life even if you don’t get cancer.”

Moreover, premature aging also can affect quality of life, he said, including cognitive function, mobility, and even nutrition and social connectivity.

According to Dr. Dai and Dr. Chen, future research may also include the effect of passive smoking on tissue self-repair, regeneration, and aging.

“The more we understand the genomics of cancer, the closer we are to bringing the best treatment or prevention plan to each individual,” said Dr. Nguyen.